https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72811
Bug ID: 72811 Summary: ICE on invalid C++ code on x86_64-linux-gnu (internal compiler error: in instantiate_type, perform_implicit_conversion_flags) Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: chengniansun at gmail dot com Target Milestone: --- $ g++-trunk -v Using built-in specs. COLLECT_GCC=g++-trunk COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto --prefix=/usr/local/gcc-trunk --disable-bootstrap Thread model: posix gcc version 7.0.0 20160805 (experimental) [trunk revision 239162] (GCC) $ $ g++-trunk small.C small.C:2:15: internal compiler error: in instantiate_type, at cp/class.c:8248 } a = C::C ?: 0; ^ 0x750d0e instantiate_type(tree_node*, tree_node*, int) ../../gcc-source-trunk/gcc/cp/class.c:8245 0x681bb4 perform_implicit_conversion_flags(tree_node*, tree_node*, int, int) ../../gcc-source-trunk/gcc/cp/call.c:9748 0x69067f build_conditional_expr_1 ../../gcc-source-trunk/gcc/cp/call.c:4806 0x69244c build_conditional_expr(unsigned int, tree_node*, tree_node*, tree_node*, int) ../../gcc-source-trunk/gcc/cp/call.c:5231 0x7d5bd0 build_x_conditional_expr(unsigned int, tree_node*, tree_node*, tree_node*, int) ../../gcc-source-trunk/gcc/cp/typeck.c:6279 0x7abd53 cp_parser_question_colon_clause ../../gcc-source-trunk/gcc/cp/parser.c:9047 0x7abd53 cp_parser_assignment_expression ../../gcc-source-trunk/gcc/cp/parser.c:9083 0x7abf9a cp_parser_constant_expression ../../gcc-source-trunk/gcc/cp/parser.c:9347 0x7ac754 cp_parser_initializer_clause ../../gcc-source-trunk/gcc/cp/parser.c:20885 0x7adf7b cp_parser_initializer ../../gcc-source-trunk/gcc/cp/parser.c:20825 0x7bfa8d cp_parser_init_declarator ../../gcc-source-trunk/gcc/cp/parser.c:18690 0x7c0631 cp_parser_simple_declaration ../../gcc-source-trunk/gcc/cp/parser.c:12415 0x7c095a cp_parser_block_declaration ../../gcc-source-trunk/gcc/cp/parser.c:12283 0x7ca294 cp_parser_declaration ../../gcc-source-trunk/gcc/cp/parser.c:12180 0x7c8b76 cp_parser_declaration_seq_opt ../../gcc-source-trunk/gcc/cp/parser.c:12059 0x7c8eac cp_parser_translation_unit ../../gcc-source-trunk/gcc/cp/parser.c:4350 0x7c8eac c_parse_file() ../../gcc-source-trunk/gcc/cp/parser.c:37549 0x92cc32 c_common_parse_file() ../../gcc-source-trunk/gcc/c-family/c-opts.c:1070 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <http://gcc.gnu.org/bugs.html> for instructions. $ cat small.C struct C { } a = C::C ?: 0; $